Clydesdales and carbon fiber-bad idea?

Discussion in 'Clydesdales 200lb / 90kg + riders' started by fatandslow, Oct 9, 2009.

  1. xpc316e

    xpc316e New Member

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    I weigh 260 lbs and recently bought a bike with an aluminium frame, carbon forks and carbon seat stays. I love the way it rides; it is as comfortable as my Dahon folder with front & rear suspension. The bike is stable, but alive in a really inspiring way.

    Losing a few pounds from the weight of your bike has a far greater effect than losing the same weight from your body. Try riding a bike with lightweight wheels to find out how a small amount of mass removed from those large, rotating flywheels at each end of the machine can radically change things.

    I have no worries about either the strength of carbon, or about other riders thinking I am too heavy to ride a light bike. If you want carbon, buy it and enjoy it!
     


  2. alienator

    alienator Well-Known Member

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    Total BS. It's been shown that the effect on bike acceleration on lighter wheels is small. Proof.

    Your advice is about the worst a person could give.
     
  3. xpc316e

    xpc316e New Member

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    That's just so pleasant of you to reply to my post in such a reasoned, polite manner. Your beautiful way of interacting with others goes a long way in continuing the special relationship that exists humans with a common interest. I love you too.:rolleyes:
     
  4. xpc316e

    xpc316e New Member

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    Having looked at your link to the mathematcial proof that my post is BS, as you so eloquently describe it, may I point out that the proof that you cite deals with climbing hills and rotational mass? I was talking about the acceleration of rotating mass - it is a totally different thing.

    I was also writing about the liveliness of a light bike: it is far more enjoyable for me (at 260 lbs) to ride a 17 lbs bike than it is for a 240 lbs me to ride a 37 lbs bike. Perhaps you can find a mathematical proof that my enjoyment of a lightweight bike is also BS, but I doubt it.

    My advice was for the OP to buy a lightweight carbon bike if he wished - that is not 'about the worst advice a person could give'. You may disagree with my opinions about light bikes and cite mathematical proof of your own ideas. That doesn't make my advice, about buying a bike and enjoying it for what it is, the worst a person could give.

    Perhaps the worst advice a person could give would be to recommend joining an internet forum discussion whilst simultaneously expecting sound reasoning and good manners.
     
  5. alienator

    alienator Well-Known Member

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    Actually, you're 100% wrong. The equation listed in the link is an equation of motion for a bicycle, and it's valid whether the bike is being pedaled on the flats, uphill, downhill, or where ever.

    Alas, you didn't say anything about it being far more enjoyable for you. What you said was this:
    A few pounds. A few pounds is 20? There is no difference losing static weight from your body or from the bike. As for rotational weight, the equation I supplied in the link shows just how small that effect is. It's very small. As for those "large, rotating flywheels," they have a very small mass moment of inertia, meaning their effect on acceleration is not large. On the flats, their effect is even smaller as accelerations are limited. There is no reason for their to be a "radical" change as a result in switching to wheels with a smaller MOI.

    Ah, but then you ventured into wild imaginings when you made claims about "radical changes" and the like.

    Don't worry. If you work at it, you can improve your reasoning. And I wasn't rude. I stated in simple words that you were wrong about your claims about performance gains and that your advice was bad. The thread revolves around road bikes. Unless a person does their road bike shopping at Walmart or some other discount department store, they're going to find that the vast majority of bikes, now, weigh in at less than 20 lbs. Given that this is clydesdale sub-forum, i.e. one having to do with riders that weigh 200 lbs +, that means the overwhelming majority of people in the sub-forum will have or be looking--if they're shopping for a road bike--at buying something that is only 1% or less of their body weight, or roughly 9% or less of the total bike/rider system weight. That means the bicycle and any and all of its components--uhm, including the wheels--will have a small effect on performance. Very small. Rider weight is the major influence, behind aero drag (in all situations except for climbs exceeding approximately 8-10% in grade), for any bicycle, on acceleration. Full stop.

    If you state your opinion as fact, as you did, you should expect that it might be challenged. I said absolutely nothing about your enjoyment of your ride.
     
  6. xpc316e

    xpc316e New Member

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    Well Alienator, you know what they say - 'there's none so blind as him who will not see'.

    You may not be sufficiently attuned to your machine as to be aware of what you deem to be small effects on performance, but that does not necessarily apply to the rest of us.
     
  7. alienator

    alienator Well-Known Member

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    Well, since you've yet to make an objective argument, there's nothing to "see" in what you've stated. It seems now you want to talk about "awareness," which is an inherently subjective topic. There is nothing objective in what your "awareness" tells you. In fact, human sensory perception is entirely susceptible to bias, emotion, fatigue, hydration, and any of tens or hundreds of factors. I've not said, before this post, one thing about "awareness" or what someone feels on a bike in this thread. Not one. I've talked about the physical reality.

    You seem to confuse your perception with fact. I can now only assume that when you stated, "Losing a few pounds from the weight of your bike has a far greater effect than losing the same weight from your body. Try riding a bike with lightweight wheels to find out how a small amount of mass removed from those large, rotating flywheels at each end of the machine can radically change things." you were talking about your "awareness". That's the rub: people who present their opinions as fact, when they are merely opinion. You should have stated as much.

    You've in no way shown how generic "lightweight" wheels make "radical" changes. You've in no way shown how losing weight off the bike is much better than losing it off your body. Hell, you've yet to make a single, cogent argument. You've slung some spray, so I guess that means that's all you've got to offer.
     
  8. GT Fanatic

    GT Fanatic New Member

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    I know, it sucks, but Alienator is actually right. Lighter wheels do make a significant difference in performance. It's basic physics 101. Less rotational mass will not only make for great efficiency from a handling perspective, but also from an accelerative one. This also applies to automobiles. Wheels are considered "unsprung weight." The lighter wheels not only aid in acceleration and handling, but also in braking situations.

    You're not the only person he tries to flex his "internet muscles" to. Look closely, and you'll see those internet-enhanced arm muscles" still represent nothing more than spaghetti noodles.
     
  9. alienator

    alienator Well-Known Member

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    Awesome! I love the opportunity to learn! Please tell me about the basic physics of bicycle wheels and rotational mass! Oh, and don't leave anything out, especially about that "greater efficiency from a handling perspective!" I can't wait to soak up the knowledge from your wise words! I wait with bated breath! Tell me all about "physics 101!" You must have a wealth of knowledge from all of your experience!
     
  10. GT Fanatic

    GT Fanatic New Member

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    It looks like you've finally learned! ;)

    I'm proud of you! You're finally learning the ways of the Force! And yes, I do have a wealth of knowledge, and who do I have to thank for it but you. :rolleyes: During my short tenure here, not only have you shown me the ways of the road, but you have greatly educated not only myself, but others on how to be an internet tool. I commend you, oh Great One.
     
  11. Mister2pi

    Mister2pi New Member

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    Here's my 2 cents:

    I've been riding on carbon frames for the past 250 miles (50/50 between a Giant and a Cannondale) and so far, no crashes, and no strange failures to speak of on the frame or the wheels (both sets have fairly low spoke counts). Just as a point of reference, I weighed 250 when I started riding and now weigh about 230.

    After speaking with quite a few mechanics and repair technicians, they seem to agree that some of the incidents that caused the breaks found on the website mentioned by the OP would wreak havoc on an aluminum frame as well. Regarding a rider's weight, just stick to the limits mentioned in the manufacturer's manuals, which are normally 300 pounds for carbon frames.

    I spent an equal amount of time on both aluminum and carbon frames in the parking lots outside of the LBS and couldn't tell a huge difference. I could tell a big difference when I rode my friend's aluminum bike after I bought my carbon bikes. I can more easily attain higher speeds on the carbon bikes with lighter frames, components and wheels (duh), and generally, the heftier bottom brackets on my bikes made power transfer a bit easier and hill climbing not as tough.

    And no, I have no mathematical proofs to offer.
     
  12. CDA 455

    CDA 455 New Member

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    /img/vbsmilies/smilies/biggrin.gif /img/vbsmilies/smilies/biggrin.gif
     
     
  13. i12ride

    i12ride New Member

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    I weigh 210 give or take 5-10 depending on summer or fall. I have pounded aluminum frames to death off road in all kinds of nasty for decades. Still have several hard tails from 1992,93,94 & 2001 that are ridden regularly. Never (knocks on wood) have had any frame issues. I currently have just resurrected a 1995 Trek Y-22 carbon fiber/aluminum frame full suspension bike and am enjoying the hell out of it on the same crazy off road stuff without issue(so far) in the 200 or so miles I've put on it. My road bike is a Specialized Allez sport which is full aluminum frame with carbon frok. I am more concerned about my wheelset holding up than my frame. I've added cf stem/bars/seatpost/cranks/cages & Ti eggbeater clipins. I have taken it from 21.5 to 18.5 lbs. I have no concerns about the carbon parts whatsoever nor would I have any concerns over jammin a full cf frame around (maybe next road or TT bike). Now, there may be more to worry about cf surviving any crashes better than steel or aluminum but as far as just riding...nah.
     
  14. dougmcbride

    dougmcbride New Member

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    Don't worry about it , OP. You're at the "small" end of the Clydesdale spectrum anyway --- Any of the better carbon frames out there will take your weight (I am leery of the no name $5-700 ebay specials i have seen though)

    I also caught the dispute about bike weight, wheel weight, etc. ----- its pretty simple really, take a 17 lb. Orbea Orca (or any number of nice bikes) with lightweight wheels , then bolt on a set of wheels from a $500 entry level machine with wire bead tires. The difference will be very real . Maybe not in the parking lot, but on a 10 mile ride the difference will be evident -- unless the ride is Kansas-flat

    (wow - just noticed this is my first post and i've been a member since 12/03-- geez)
     
  15. Thylacine

    Thylacine Member

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    I'm amazed anyone over 200lbs can find a bike to fit them, let alone 'take the weight'.
     
  16. swampy1970

    swampy1970 Well-Known Member

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    Thylo,

    You need to build a Clydesdale bike with a 'gunt bar'TM - a toptube that slopes down in the middle a bit like the suspension cables on the Golden Gate bridge. Equip it with DA2 so the flex from having a behemoth riding it doesn't cause the cables to alter tension and change gear with every pedal stroke...
     
  17. Thylacine

    Thylacine Member

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    I think Dario is on the right track with behemoth chainstays, except he's too Italian to realise that once you've done that, you can waste away the seatstays to nothing. That takes Canadians. To do it in steel however takes.......an Aussie. :)

    Nev knows what happens with Canadians try to do steel these days.
     
  18. frbock

    frbock New Member

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    Out of curiosity, I went to one of the manufacturers that actually lists some of the frame weights (Formigili), and it's pretty close
    kevlar 1,1 - 1,25 KGs.
    Aluminum 1.050 - 1.100 kg
    Steel 1.380 kg.
    Carbon 1.050 - 1.100 kg

    carbon to steel .4 kg, or about a lb. Granted the carbon bike is decked with the ultra lightweight everything else, but, you could deck out a steel frame the same way.
     
  19. doctorold

    doctorold Member

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  20. m0b00st

    m0b00st New Member

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    This thread has almost made me lose my faith in this forum board.

    First you have some dimwit that posts a link of broken carbon bikes and thinks it the end all be all of what will happen to a carbon bike.
    - Fact: The amount of force it takes to shear a carbon bike like in those pictures is actually higher than the amount of force needed to render an aluminum frame worthless.

    Secondly, we have some asshat that thinks by posting a link he has refuted the common knowledge of the entire world in regaurds to rotational mass and unsprung weight.
    - Alienator: Are you seriously trying to argue the fact that lighter wheel and tire setups dont equate to all around better performance no matter what the application? If so, you might want to take this wealth of knowledge you have and sell it to the thousands of race teams out there that are clearly wasting their money with their R&D departments. While your at it maybe you could make a tour to any and all club racing events where enthusiasts from all walks of life and in many different racing forms share the common knowledge that THE SINGLE BIGGEST DIFFERENCE in handling, cornering and acceleration will be noticed from the changes made by lightening wheels and tires. Its such common knowledge that there are specific racing classes in which automobiles must be raced completely stock, but allow for changes to wheels and tires only.


    All I have to say about this thread is "WOW"

    PS - I would be willing to bet that larger riders would notice the benefits of a CF frames ride quality over an AL one much easier than a lighter rider would.
     
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